My two Debian desktop PCs have recently started exhibiting undesirable behaviour:- I have automatic suspend enabled, and when I try to resume after an extended suspension I keep finding them in what appears to be a state of hibernation. They start in grub and go through a sort of boot sequence which can take even longer than a normal boot, before presenting the desktop I left. I think this is also responsible for the PC in my bedroom waking me up in the middle of the night by bursting into life for a few seconds, as it switches from suspend to hibernate I guess.

I was happy with plain old suspend, how can I disable this behaviour? I've looked at the changelogs for systemd, gnome-shell, gnome-settings-daemon, gnome-shell and gdm. The only one which matches "hibernat*" for recent changes is gnome-settings-daemon - "Add SuspendAndHibernate" - and that was back in July, whereas I have only noticed this problem in the last week or so.

I did find some information about hybrid, but I don't think that's what's going on here, or if it is it isn't working how I would like it to. What I understand hybrid should do is when triggered, first prepare for hibernation, but just before stopping the CPU go into suspend instead. If nothing happens the PC should stay in suspend mode until resumed (rather than drop into hibernation a bit later like mine), and the hibernation is a sort of mini back-up in case the power fails while suspended.

In the meantime I've done systemctl mask hibernate.target, I'll see if that helps.

It didn't, but then I noticed there was a suspend-then-hibernate.target which sounds like a plausible culprit. I think masking it would prevent (GNOME's) suspend from working at all, so I need to find what's responsible for calling suspend-then-hibernate instead of suspend and/or hack systemd to make suspend-then-hibernate do suspend only. Seeing how systemctl mask works I presume I could do this by:

My system is sid, I appear to have done a dist-upgrade at an awkward time because I have a mixture of 3.28.1-1 and 3.30.0 GNOME packages. systemd is 239-9. This PC is a 1st gen Ryzen5 on a B350 chipset with NVidia 1060 GPU using the proprietary driver, 16GB RAM, one M2+SATA SSD, and one SATA SSD, Debian is on the latter IIRC. The other PC is based on an Intel G4560, I use the onboard graphics. It has two SATA SSDs. I haven't updated the OS as recently as this one. So two quite different systems, I don't think this is hardware specific.